1. Field of the Invention
The present invention relates to an ink jet recording apparatus in which an ink-jet recording head ejects ink droplets to record on a recording medium, and to an ink jet recording method in which the ink jet recording apparatus is used.
2. Description of the Related Art
An ink jet recording apparatus selectively ejects ink droplets from multiple nozzles while a recording head is reciprocally moved in main scanning directions and recording paper is conveyed in a sub-canning direction, so that characters and images are recorded on the recording paper. The recording head ejects the ink by using various actuators. For example, a method in which ink droplets are ejected from a nozzle that communicates with a pressure chamber by applying pressure to the pressure chamber with a vibrator plate by the use of a piezoelectric element, and a method in which, using a heat-generating element, ink droplets are ejected using heat generated by the heat-generating element, are known.
When ink jet recording apparatuses of these types are allowed to stand for a long time, moisture in the ink evaporates with the result that the ink dries via the nozzle of the recording head. Since the viscosity of the ink increases when the ink dries, the ink is no longer ejected under a normal ink-discharging pressure, which causes printing defects. For this reason, the recording head is covered with a cap when the apparatus is not used so as to prevent the ink from drying within the nozzle. However, this method is insufficient for solving the problem.
In order to solve this problem, (1) a method in which, while the recording head is withdrawn to a non-printing area, the ink within the nozzle is refreshed by discharging ink having increased viscosity (a purging operation) and (2) a method in which, in a non-driving state, the meniscus face is vibrated to a degree at which ink is not ejected so that the ink having an increased viscosity is stirred (application of preliminary waveform) have been disclosed (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2002-019104, JP-A No. 57-061576 and JP-A No. 2000-168103).
In accordance with the method (1) above, when the ink recovered from the recording head is discarded without being reused, ink is wastefully used and frequent ink-cartridge replacements are required, resulting in disadvantages from the economic point of view.
For this reason, various techniques in which the waste ink is reused to prevent wasteful use of ink resources have been proposed (for example, see Japanese Patent Application Laid-pen (JP-A) No. 2000-272144, JP-A No. 2002-19154, JP-A No. 2002-86763 and JP-A No. 2002-200771). These conventional reusing methods relate to techniques for adjusting the viscosity of waste ink and for filtering the waste ink through a filter and, as such, techniques in which volatile components are replenished based upon conductivity and specific gravity when reusing the waste ink have not been disclosed.
The invention has been devised so as to solve the above-mentioned problems, and provides an ink jet recording apparatus and an ink jet recording method which can reuse waste ink derived from an ink jet recording head of an ink jet recording apparatus.